Multifunctional flexible sensor array-based damage monitoring for switch rail using passive and active sensing

Pan Hu, Haitao Wang, Guiyun Tian, Yang Liu, Xin Li, Billie F. Spencer

Research output: Contribution to journalArticlepeer-review


A passive monitoring technique for switch rails will be very attractive because it does not require extra excitations and can realize large area monitoring. However, complex wheel-rail interactions and sparse sensors will affect the accuracy of local damage identification. In contrast, an active monitoring technique has high local damage quantification ability but has low efficiency for large area monitoring. This study firstly presents a combination of piezoceramic material Lead zirconate titanate (PZT) wafers with accelerometers to configure a multifunctional sensor array that brings together active and passive monitoring mechanisms. The multifunctional sensor arrays are produced in a flexible form, which are adapted to complex geometry and are easy to install. In complementary passive monitoring, each sub area's health state between 2 accelerometers is represented by reconstructing transfer functions, which are calculated from rail vibrations. The reconstructed transfer function in conjunction with principal component analysis (PCA)-based feature extraction is utilized for estimating the damaged sub area. Then accurate local damage identification can be realized through the active guided waves technique and correlation-based diagnostic imaging in conjunction with singular value decomposition (SVD). Simulation and experimental studies show the proposed mechanisms can identify the damaged sub area and basically extract damage locations with different lengths correctly with the sparse sensor array. Finally, based on a controlled experiment, the causes of the errors are evaluated and analyzed. The proposed mechanism can simplify data analysis, save monitoring time, and decrease the final cost.

Original languageEnglish (US)
Article number095013
JournalSmart Materials and Structures
Issue number9
StatePublished - Sep 2020


  • guided waves
  • multifunctional flexible sensor array
  • passive and active monitoring
  • principal component analysis (PCA)
  • reconstruct transfer function

ASJC Scopus subject areas

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering

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